This study is for people with a heart condition called transthyretin amyloid cardiomyopathy (ATTR-CM), which affects the heart's ability to pump blood well. The research will test a new medicine, NNC6019-0001, to see if it can help lower the chances of heart-related problems or death. Participants will get either the new medicine or a placebo, which is a fake treatment with no real medicine in it. Neither the participants nor the doctors will know who gets which treatment. Everyone will keep taking their usual heart medicines as per their doctor's advice.

• The study requires participants to be 18 years or older with a confirmed diagnosis of ATTR-CM.
• Participants must not have been part of previous studies for similar treatments.
• The study involves regular monitoring and tests, so participants need to be open to follow-ups.